Systems and methods for administering medication

ABSTRACT

The syringe systems disclosed herein provide in part devices for allowing patients with compromised joint strength to more easily administer medicine. Certain exemplary syringe embodiments include a handle forming a handgrip, a syringe barrel that magnifies the dosage marks located on an inner barrel, and a tip cap slidably engageable with the syringe barrel for shielding a needle.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.12/317,833 filed Dec. 29, 2008, now U.S. Pat. No. 8,579,866, whichclaims the benefit of priority of U.S. provisional application Ser. No.61/010,779 filed Jan. 11, 2008, U.S. provisional application Ser. No.61/135,262 filed Jul. 18, 2008, and U.S. provisional application Ser.No. 61/192,551 filed Sep. 18, 2008. The disclosures of each of theforegoing applications are hereby incorporated by reference in theirentirety.

BACKGROUND

Rheumatoid arthritis (“RA”) is an autoimmune disease characterized bychronic inflammation of the joints leading to progressive cartilagedestruction and bone erosion. RA patients experience joint pain,stiffness, and swelling. More advanced RA causes the joint to lose itsshape, alignment, and movement. RA has been treated for many years witha variety of medicines such as steroids and disease modifyingantirheumatic drugs (DMARDs). Some of these drugs are administeredthrough injections or infusions. However, it is difficult for RApatients with compromised joint strength and structure to manipulateavailable syringes to perform a self injection, particularly for viscousbiologics and other drugs. Currently, some drugs are injected usingconventional hypodermic syringes. These conventional syringes aregenerally small, which makes holding or manipulating the syringe moredifficult. These syringes also do not provide RA patients withsatisfactory handling and gripping structures.

In addition, typical syringes are difficult for some patients to de-capand re-cap. For example, most needles come with a needle tip cover thatshields the needle prior to use, but the cover requires RA patients toforce their fingers to close in around the needle tip cover tomanipulate the cover. Because these needle tip covers have smallopenings, patients frequently accidentally stab themselves when they tryto shield the needle after use.

More effective syringe systems are needed to address these and otherproblems posed by currently available syringe systems. There is a needfor a syringe system that allows the patient to more easily administer aviscous drug, yet still provide increased safety as well as increasedcontrol. There is also a need for syringe systems that provides moreergonomic gripping compatibility for RA patients.

SUMMARY OF THE INVENTION

The syringe systems disclosed herein address various deficiencies in theprior art by, in various embodiments, providing improved syringe systemsthat allows patients to more easily administer medicine, particularlypatients with, for example, compromised dexterity or joint strength. Inone representative embodiment, a syringe system is provided with ahandle having a first flange and a second flange that forms a handgrip.The handle also includes a first arc forming a bottom surface of thefirst flange contoured to correspond to a radius of an arc formed by auser's fingers and a second arc forming a bottom surface of the secondflange contoured to correspond to a radius of an arc formed by theuser's fingers and shaped flatter than the first arc. In certainembodiments, the second flange is 1.5 times as long as the first flange.The syringe system also includes a syringe barrel having an outer barreland an inner barrel. The inner barrel includes dosage marks and a needlemounted at a distal end and the outer barrel is shaped to receive theinner barrel and has an elliptical cross section to magnify the dosagemarks located on the inner barrel.

The syringe system includes a tip cap slidably engageable with a distalend of the syringe barrel for shielding the needle having an outer cap,an inner cap, and a connector. The connector is shaped to fit within andengage the outer cap and engage the inner cap and includes a pluralityof first legs spaced symmetrically away from one another, each first leghaving a plurality of internally facing barbs pointing toward a distalregion of the connector and adapted to engage a proximal region of theinner cap. The plurality of internally facing barbs may be disposed atan angle with respect to the plurality of the first legs. The connectoralso includes a plurality of second legs spaced symmetrically away fromone another, each second leg having a plurality of externally facingbarbs located in the distal region of the connector and adapted toengage a distal region of the outer cap. In certain embodiments, theplurality of first legs are biased initially at about 80 degrees withrespect to the horizontal.

According to one implementation, the outer barrel includes a firstrecess and a second recess shaped to receive the tip cap. In certainembodiments, the outer cap includes a first protrusion and a secondprotrusion formed on an inner surface of a shoulder formed on the outercap to interfit with the first recess and the second recess of the outerbarrel, respectively In certain embodiments, the outer cap includes agripping ring, which may be shaped to receive the user's thumb or otherpreferred finger to engage the ring. In certain embodiments, thegripping ring is shaped to receive a hook.

According to one implementation, the outer barrel includes a distalaperture to allow the inner barrel to extend through the aperture. Theouter barrel has a major diameter and a minor diameter. In certainembodiments, the major axis of the syringe barrel is longer than a minoraxis of the syringe barrel. In certain embodiments, the ratio betweenthe major diameter and the minor diameter is 1.5:1. In certainembodiments, the inner barrel is positioned within the outer barrel suchthat the dosage marks are oriented at one end of the major diameter formagnifying the dosage marks.

According to one implementation, a syringe system includes a handlehaving a first flange and a second flange that forms a handgrip. Thehandle also includes a first arc forming a bottom surface of the firstflange contoured to correspond to a radius of an arc formed by a user'sfingers and a second arc forming a bottom surface of the second flangecontoured to correspond to a radius of an arc formed by the user'sfingers and shaped flatter than the first arc. The syringe system alsoincludes a tip cap slidably engageable with a distal end of the syringebarrel for shielding the needle. In certain embodiments, the tip capincludes an outer cap, an inner cap, and a connector shaped to fitwithin and engage the outer cap and engage the inner cap and optionallyincludes a plurality of first legs spaced symmetrically away from oneanother, with each first leg having a plurality of internally facingbarbs pointing toward a distal region of the connector and being adaptedto engage a proximal region of the inner cap, where the plurality ofinternally facing barbs are disposed at an angle with respect to theplurality of first legs. The connector also includes a plurality ofsecond legs spaced symmetrically away from one another, each second leghaving a plurality of externally facing barbs located in the distalregion of the connector and adapted to engage a distal region of theouter cap.

According to one implementation, the syringe system includes a handlehaving a first flange and a second flange that forms a handgrip. Thehandle also includes a first arc forming a bottom surface of the firstflange contoured to correspond to a radius of an arc formed by a user'sfingers and a second arc forming a bottom surface of the second flangecontoured to correspond to a radius of an arc formed by the user'sfingers and shaped flatter than the first arc. The syringe system alsoincludes a syringe barrel having an outer barrel and an inner barrel andextending distally from the handgrip, the inner barrel having dosagemarks and a needle mounted at a distal end, and the outer barrel beingshaped to receive the inner barrel and having an elliptical crosssection to magnify the dosage marks located on the inner barrel. Incertain embodiments, the handle of the syringe system includes a topcover and a handle body. The top cover includes a plurality of pegsadapted to mate with a set of corresponding depressions formed on thehandle body. In certain embodiments the top cover includes an aperturefor receiving a syringe plunger and the handle body includes an aperturefor receiving a syringe plunger. In certain embodiments, the handle bodyincludes a syringe positioning pocket having a flat side and the innerbarrel includes a flange having a flat side adapted to align withcorresponding flat sides formed on the handle body. In certainembodiments, aligning the flange within the syringe positioning pocketorients the dosage marks at one end of a major axis of the syringebarrel.

According to one implementation, a syringe system includes a syringebarrel having an outer barrel and an inner barrel, the inner barrelhaving dosage marks and a needle mounted at a distal end. The outerbarrel is shaped to receive the inner barrel and has an elliptical crosssection to magnify the dosage marks located on the inner barrel. Thesyringe system also includes a tip cap slidably engageable with a distalend of the syringe barrel for shielding the needle, including an outercap, an inner cap, and a connector shaped to fit within and engage theouter cap and engage the inner cap. The connector has a plurality offirst legs spaced symmetrically away from one another, with each firstleg having a plurality of internally facing barbs pointing toward adistal region of the connector. The plurality of internally facing barbsare disposed at an angle with respect to the plurality of first legs andthereby adapted to engage a proximal region of the inner cap. Theconnector also includes a plurality of second legs spaced symmetricallyaway from one another, where each second leg has a plurality ofexternally facing barbs located in the distal region of the connectorand is adapted to engage a distal region of the outer cap.

According to one implementation, a syringe barrel includes an outerbarrel and an inner barrel. The inner barrel includes dosage marks and aneedle mounted at a distal end and the outer barrel is shaped to receivethe inner barrel and has an elliptical cross section to magnify thedosage marks located on the inner barrel.

According to one implementation, a tip cap that is slidably engageablewith a distal end of a syringe barrel for shielding the needle includesan outer cap, an inner cap, and a connector shaped to fit within andengage the outer cap and engage the inner cap. The connector has aplurality of first legs spaced symmetrically away from one another, witheach first leg having a plurality of internally facing barbs pointingtoward a distal region of the connector. The plurality of internallyfacing barbs are disposed at an angle with respect to the plurality offirst legs, and are therefore adapted to engage a proximal region of theinner cap. The connector also includes a plurality of second legs spacedsymmetrically away from one another, where each second leg has aplurality of externally facing barbs located in the distal region of theconnector and is adapted to engage a distal region of the outer cap.

According to one implementation, a drug delivery system is provided,including a syringe barrel having an outer barrel and an inner barrel.The inner barrel has dosage marks and a needle mounted at a distal end,the outer barrel is shaped to receive the inner barrel and has anelliptical cross section to magnify the dosage marks located on theinner barrel. In certain embodiments, the inner barrel is adapted toreceive a drug having a viscosity more than about 65 centipoise. Incertain embodiments, the viscosity of drug is between about 65centipoise to about 120 centipoise. In certain embodiments, theviscosity of drug is between about 75 centipoise to about 100centipoise.

The drug delivery system also includes a tip cap slidably engageablewith a distal end of the syringe barrel for shielding the needle. Thetip cap has an outer cap, an inner cap, and a connector shaped to fitwithin and engage the outer cap and engage the inner cap. The connectorhas a plurality of first legs spaced symmetrically away from oneanother. Each first leg has a plurality of internally facing barbspointing toward a distal region of the connector and is adapted toengage a proximal region of the inner cap. In certain embodiments, theplurality of internally facing barbs are disposed at an angle withrespect to the plurality of first legs. The connector also includes aplurality of second legs spaced symmetrically away from one another,where each second leg has a plurality of externally facing barbs locatedin the distal region of the connector and is adapted to engage a distalregion of the outer cap.

According to one implementation, a syringe system is disclosed as havinga handle with a first flange and a second flange forming a handgrip, afirst arc forming a bottom surface of the first flange contoured tocorrespond to a radius of an arc formed by a user's fingers and a secondarc forming a bottom surface of the second flange contoured tocorrespond to a radius of an arc formed by the user's fingers and shapedflatter than the first arc. The syringe also includes a syringe barrelhaving an outer barrel and an inner barrel, the inner barrel havingdosage marks and a needle mounted at a distal end, the outer barrelshaped to receive the inner barrel and having an elliptical crosssection to magnify the dosage marks located on the inner barrel. Theouter barrel includes proximal and distal ends and a recess formed atthe distal end. The syringe also includes a tip cap for shielding theneedle, the tip cap having a shoulder including an inner surface and anouter surface and a mating protrusion that is formed on the innersurface and is shaped to matingly engage with the recess formed on theouter barrel. In certain embodiments, the tip cap includes an inner capthat is received within the outer cap. In certain embodiments, the innerbarrel is disposed within the tip cap when the tip cap mates with theouter barrel. In certain embodiments, the outer barrel has a distalopening and the inner barrel protrudes through the distal opening whenthe syringe assembly is fully assembled.

According to one implementation, the outer barrel has a first recess anda second recess. The outer barrel also has a major diameter and a minordiameter, and the first recess is formed at first end of the majordiameter and the second recess is formed at an opposite end of the majordiameter. The mating protrusion of the tip cap includes a top surfaceand a side surface, the side surface being positioned perpendicular tothe longitudinal axis of the handle. In certain embodiments, the matingprotrusion has a triangular cross sectional area. The syringe alsoincludes a tip cap that includes an inner cap, an outer cap, and aconnector shaped to fit within and engage the outer cap and engage theinner cap. The tip cap has a plurality of first legs spacedsymmetrically away from one another, with each first leg having aplurality of internally facing barbs pointing toward a distal region ofthe connector and each leg being adapted to engage a proximal region ofthe inner cap. The plurality of internally facing barbs are disposed atan angle with respect to the plurality of first legs. The connector alsoincludes a plurality of second legs spaced symmetrically away from oneanother, each second leg having a plurality of externally facing barbslocated in the distal region of the connector and adapted to engage adistal region of the outer cap.

In certain embodiments, the tip cap includes a stem portion extendingdistally from the shoulder having a cylindrical shape. The inner cap andthe connector are received within the stem portion.

These and other features and advantages of the invention are describedin further detail below with regard to illustrative embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

The following Figures depict illustrative embodiments of the inventionin which like reference numerals refer to like elements. These depictedembodiments may not be drawn to scale and are to be understood asillustrative and not limiting.

FIGS. 1A-1D depict various views of a syringe system according to anillustrative embodiment of the invention.

FIG. 1E depicts an alternative embodiment of a syringe system.

FIG. 2A depicts an exploded view of a handle assembly of the syringesystem depicted in FIGS. 1A-1D.

FIGS. 2B-2C depict underside and side views of an exemplary embodimentof a top cover of the handle assembly as depicted in FIG. 2A.

FIG. 2D shows a top view of an exemplary embodiment of the handleassembly as depicted in FIG. 2A.

FIG. 2E depicts a perspective view of a handle body as depicted in FIG.2A.

FIGS. 3A-3B show a patient holding the handle assembly having a plungeraccording to an illustrative embodiment of the invention.

FIGS. 4A-4C depict various views of a plunger as depicted in FIGS.1A-1D.

FIG. 5A depicts an inner barrel received in the handle assembly and theplunger being partially received within the inner barrel according to anillustrative embodiment of the invention.

FIG. 5B depicts a perspective view of an exemplary embodiment of theinner barrel of the syringe system as depicted in FIG. 5A.

FIGS. 6A-6B depict front and side views of the handle assembly asdepicted in FIG. 2A.

FIG. 7 depicts a patient holding the handle assembly between thepatient's index and the third finger of the patient's left hand.

FIG. 8 depicts a cross-section view of the syringe system as depicted inFIGS. 1A-1B.

FIG. 9 depicts an exploded view of a needle tip cap as depicted in FIG.8 showing an exemplary mating relationships between an inner cap, aconnector, and an outer cap.

FIGS. 10A-10B depict perspective and cross sectional view of anexemplary embodiment of the inner cap as depicted in FIG. 8.

FIGS. 11A-11C depict various views of an exemplary embodiment of theconnector being mated to the outer cap as depicted in FIG. 8.

FIGS. 12A-12C depict various views of an exemplary embodiment of theouter cap as depicted in FIG. 9.

FIGS. 13A-13F depict various views of an exemplary embodiment of theconnector for connecting the inner cap to the outer cap as depicted inFIG. 8.

FIG. 14 depicts a top view of an exemplary embodiment of a needle tipcap having the inner cap, the connector, and the outer cap as depictedin FIG. 8.

FIG. 15A depicts a perspective view of the needle tip cap as depicted inFIG. 14 with the outer cap removed for viewing clarity

FIG. 15B depicts a cross sectional view of a connector being receivedwithin the outer cap.

FIG. 16A depicts an exploded view of the needle tip cap mating to thehandle assembly having the plunger according to an illustrativeembodiment of the invention.

FIG. 16B depicts an enlarged view of a distal region of the handleassembly as shown in FIG. 16A.

FIG. 17A depicts an alternative embodiment of an inner cap.

FIG. 17B depicts an alternative embodiment of a needle tip cap adaptedto mate with the inner cap as depicted in FIG. 17A.

FIGS. 18A-18D depict alternative embodiments of a needle tip cap.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

To provide an overall understanding of the invention, certainillustrative embodiments will now be described, including exemplaryembodiments of a system that is adaptable to inject liquid drugs in thetreatment of a patient suffering RA or other auto-immune diseases suchas Multiple Sclerosis, Lupus, and Spondylitis. However, it will beunderstood by one of ordinary skill in the art that the systems andmethods described herein can be adapted and modified for other suitableapplications and that such other additions and modifications will notdepart from the scope hereof.

Turning to the illustrative embodiments, FIGS. 1A-1D show front, side,top, and exploded views of an exemplary embodiment of a syringe system100 used to house a syringe and needle assembly 101, which is fittedwithin the syringe system 100. The syringe system 100 includes, amongother features, a handle assembly 107 for allowing RA patients to gripthe syringe system 100 comfortably, a plunger 110 for injecting themedication contained in the syringe system 100, and a needle tip cap 112for shielding the needle assembly 101 fitted within the syringe system100 protruding from the distal end 107 b thereof. The plunger 110 andthe needle tip cap 112 are slidably engaged with respective proximal 107a and distal 107 b ends of the handle assembly 107.

FIG. 1E shows an alternative embodiment of a syringe system similar tothose shown in FIGS. 1A-1D. In particular, the syringe system 120 asshown in FIG. 1E includes, among other features, a handle assembly 122having a proximal end 122 a and a distal end 122 b, and a needle tip cap124. As shown, the handle assembly 122 includes a curved hook 126 at oneend that is shaped to facilitate the user's fingers to rest or anchorduring use. The needle tip cap 124 includes a tapering lip 128 thattapers from the interior edge 127 of the needle tip cap 124 to theexterior surface 130 of the needle tip cap 124. In the depictedembodiment, the needle tip cap 124 includes an elliptical finger ring132. The finger ring 132 may be circular or other preferred shape thatallows a user's finger or a hook to easily engage the needle tip cap124.

FIG. 2A shows an exploded view of the handle assembly 107, whichincludes a top cover 203 that is shaped to mate with a handle body 201.In the depicted embodiment, the handle body 201 is unitary polycarbonateformed, for example, using injection molding. The handle body 201includes a gripping portion 204 fused, glued, or constructedcontinuously with a syringe barrel (portion) 106.

A handgrip 102 is formed when the top cover 203 is mated to the handlebody 201 as shown in FIG. 2A. The handgrip 102 is contoured and hasproportions to fit the hand of a patient with rheumatoid arthritis, inparticular a hand of a patient that has the condition known as “SwanNeck Deformation.” The handgrip 102 is also adapted to provide RApatients with various gripping options. Compared to a conventionalhypodermic syringe, the handgrip 102 is generally larger and includescontoured gripping surfaces to allow RA patients with different syringeholding techniques to easily cradle the handgrip 102 in their hands.This is helpful to RA patients because they have “good days” and “baddays” in terms of the amount of pain and the control that they have overtheir joints. On bad days, a patient might not be able to hold thesyringe the way he or she normally does. The handgrip 102 is shaped toaccount for these situations when these patients are unable to controlcertain parts of their hand. The handgrip 102 is also provided toimprove engagement between the patient's hand and the syringe system100. The top cover 203 and the gripping portion 204, in certainembodiments, have different surface finishes, providing contrastingtextures to enhance the patient's grip. In other embodiments, thehandgrip 102 is made of rubbery or textured material, providing contactfriction to enhance the patient's grip.

The top cover 203 includes a top aperture 205 for receiving the plunger110 and a plurality of pegs 206 a-206 d for positioning and mating thetop cover 203 to the gripping portion 204. FIG. 2B shows the undersideof the top cover 203 having four pegs 206 a-206 d, which are shaped andsized to mate with corresponding depressions 208 a-208 d formed on thegripping portion 204. FIG. 2C shows a side view of the top cover 203. Inthe depicted embodiments, the pegs 206 are symmetrically positioned withrespect to the center axis of the top aperture 205. The top cover 203also includes a pair of mating pegs 207 a-207 b that mate withcorresponding depressions 209 a-209 b formed on the gripping portion204. The outer edge 211 of the top cover 203 is rounded to providesmooth transition between the top cover 203 and the gripping portion 204of the handle body 201.

FIG. 2D depicts a top view of the handle body 201 and an inside view ofthe distal surface of gripping portion 204. As shown, the handle body201 includes, among other things, a plurality of depressions 208 a-208 dthat correspond to the pegs 206 a-206 d formed on the top cover 203 anda plurality of outer depressions 209 a-209 b shaped to receive themating pegs 207 a-207 b formed on the top cover 203. The handle body 201also includes a bottom aperture 210 for receiving the plunger 110. Whenthe pegs 206 and 207 of the top cover 203 mate with the depressions 208and 209 of the handle body 201, respectively, the bottom aperture 210aligns with the top aperture 205 positioned on the top cover 203,thereby defining an orifice for receiving the plunger 110. The handlebody 201 also includes a recess lip 214 shaped to receive a matingsurface 216 of the top cover 203. FIG. 2E shows a perspective view ofthe handle assembly 107 with the top cover 203 removed, which shows therecess lip 214 being formed along the periphery of the gripping portion204 of the handle body 201. Having the recess lip 214 avoids thehandgrip 102 having sharp or protruded edges when the top cover 203mates with the handle body 201. Once mated, the top cover 203 and thehandle body 201 together form a smooth handgrip 102. This configurationis beneficial to patients, as raised surfaces or sharp edges would beuncomfortable to the patients.

The handle body 201 also includes a syringe positioning pocket 212having a flat side 212 a. As shown in FIGS. 2D-2E, the syringepositioning pocket 212 includes two flat sides 212 a disposed paralleland symmetrical about the longitudinal axis of the gripping portion 204of the handle body 201. The syringe positioning pocket 212 aids inorienting a conventional syringe having dosage marks in a manner thatmakes it easier for the patients to read the dosage marks located on thesyringe. More detailed description of the placement between the syringehaving the dosage marks and the handle body 201 is provided withreference to FIGS. 5A-5B. Similar to the top cover 203, the outer edge215 of the gripping portion 204 of the handle body 201 is also roundedand smoothed to maximize patient comfort.

As noted earlier, the handgrip 102 is formed when the top cover 203mates with the handle body 201. FIG. 3A shows the handgrip 102 having afirst flange 102 a and a second flange 102 b. The first flange 102 aincludes a first arc 204 a formed from a bottom surface of the firstflange 102 a and is contoured to correspond to a radius of an arc formedby a patient's fingers. Similarly, the second flange 102 b includes asecond arc 204 b formed from a bottom surface of the second flange 102 band having a contoured shape to correspond to the patient's fingers. Thesecond arc 204 b may be approximately 1.5 times longer than the firstarc 204 a. In other embodiments, the second arc 204 b is at least 2times as long as the first arc 204 a.

In some embodiments, the second arc 204 b has a flatter arc compared tothe first arc 204 a. Such shape allows the patient to place more fingersaround the second flange 102 b and cradle the syringe 100 comfortably.For example, FIG. 3A shows a patient holding the syringe using thepatient's index and the third and fourth fingers. As shown, thepatient's index finger is separated from the rest by the syringe barrel106. In the depicted embodiment, the patient places his index fingeragainst the first arc 204 a and the third and fourth fingers against thesecond arc 204 b. The first arc 204 a includes a first curved portion205 a that serves as an anchoring point when the patient is holding thesyringe 100 to administer medication. Using the example above, when thepatient places the index finger against the first arc 204 a, the indexfinger naturally wraps around the first curved portion 205 a and thethird finger fully or partially rests against a second curved portion205 b as shown in FIG. 3A. The patient's index and the third fingers arealso resting on the syringe barrel 106.

FIGS. 3A-3B also depict the positioning of the plunger 110 with respectto the handgrip 102. As shown in FIG. 3A, the handgrip 102 is shaped toallow the patient's thumb to comfortably sit on the plunger 110. Theplunger 110 as shown in FIG. 4A includes, among other things, a concaveplunger pad 302 located at the proximal end of the plunger 110 and aplunger stem 304 that extends from the concave plunger pad 302 to thedistal tip of the plunger 110. The concave plunger pad 302 is formed ofa plastic with a rubber overmold. The concave plunger pad 302 is shapedto receive the surface of the patient's thumb or other preferredfinger(s) or parts of the patient's hand. FIG. 3A shows the base of thepatient's thumb resting on the concave plunger pad 302. In someembodiments, the patient prefers to place his palm on the concaveplunger pad 302 for manipulating the plunger 110. FIG. 3B shows thepatient using the base of his palm for pushing the plunger 110 forejecting contained medicine. The shape of the concave plunger pad 302forms a depression for receiving the patient's finger or other parts ofthe patient's hand during the use of the syringe, which aids inpreventing the patient's finger or hand from slipping from the topsurface of the plunger pad 302, thereby making the self-injection safer.

As shown in FIGS. 4A-4B, the plunger stem 304, having a circular crosssection, tapers from the concave plunger pad 302 and is structurallysturdier than commercially available plunger rods that incorporate astructure with an “X” or “T” cross section. In certain embodiments, theplunger stem 304 is made of acrylonitrile butadiene styrene (ABS), otherco-polymers, or other suitable light-weight material. The plunger stem304 also includes a threaded portion 306 positioned at the distal end ofthe plunger stem 304. The threaded portion 306 threads into a stopperlocated in a syringe barrel of needle assembly 101 that contains themedicine. The stopper includes corresponding female threads that receivethe threaded portion 306 of the plunger stem 304 to provide secureengagement between the plunger 110 and the syringe barrel. FIG. 4C showsan enlarged view of the threaded portion 306 of the plunger 110.

FIG. 5A-5B depict the needle assembly 101 fitted within the syringesystem 100. In particular, needle assembly 101 includes an inner barrel404 fitted with a syringe needle 406. As shown in FIG. 5A, the innerbarrel 404 of the needle assembly 101 slides within the syringe barrel106 of the handle assembly 107. As depicted, the syringe barrel 106includes an aperture 408 shaped to allow the a distal end 404 b of theinner barrel 404 to extend therethrough. The extended portion of theinner barrel 404 includes a shoulder portion 405 and a distal tipportion 407. The shoulder portion 405 tapers from the distal end 404 bof the inner barrel to the distal tip portion 407 where a syringe needle406 is embedded. In certain embodiments, the inner barrel 404, theshoulder portion 405, and the distal tip portion 407 are made of glassand are formed as a unitary part. The inner barrel 404 also includesdosage marks 410 that depict volumetric levels of medicament containedin the inner barrel 404. In the depicted embodiment, the aperture 408has a circular cross sectional area, as does the inner barrel 404. Incertain embodiments, when the inner barrel 404 is fitted within thesyringe barrel 106, the two components form a space having a ring shapedcross sectional area between the outer surface of the inner barrel 404and the inner surface of the syringe barrel 106.

As more particularly illustrated in FIG. 5B, the inner barrel 404includes proximal 404 a and distal 404 b ends and also an inner syringebarrel flange 412 having flat sides 412 a and curved sides 412 b formedon the proximal end 404 a. In certain embodiments, the inner syringebarrel flange 412 controls the orientation of the inner barrel 404within the syringe barrel 106. This is done by placing the inner barrel404 within the syringe barrel 106 so that the flat sides 412 a of theinner syringe barrel flange 412 mate with the corresponding flat sides212 a of the syringe positioning pocket 212 located on the handle body201.

FIGS. 6A-6B and 7 depict various views of the handle body 201 having amajor axis (or “diameter”) 422 and a minor axis (or “diameter”) 420forming an oval cross section. The major axis 422 is longer than theminor axis 420. The minor axis 420 runs parallel to the length of thehandgrip 102, such that the major axis 422 runs parallel and between thepatient's fingers during administration and perpendicular to thelongitudinal axis of the handgrip 102. This alignment provides stabilityto the syringe in the patient's hand during administration, which isbelieved to be beneficial for arthritic patients. This alignment alsoprovides increased control to patients by providing greater contactsurface area between the patient's fingers and the syringe 100. This isdone by positioning the syringe 100 in the configuration as shown inFIG. 7. More specifically, the longer side (i.e., the major axis 422running parallel to the patient's fingers) of the syringe barrel ispositioned between the patient's fingers, which allows the syringe 100to rotate less in patient's hand compared to a standard syringe having acircular cross-sectional area. The elliptical cross section of thesyringe barrel 106 also allows the syringe barrel 106 to fit morecomfortably within the patient's hand for easier administration. Incertain embodiments, the major axis 422 is about 14.9 mm and the minoraxis 420 is about 11.5 mm. In certain embodiments, the ratio of thelength of major axis 422 to the length of the minor diameter 420 isabout 1.1:1, about 1.2:1, about 1.3:1, about 1.5:1, or even about 2:1.

As noted earlier, one of the objectives of the present syringe system isto improve the visibility of the dosage marks for the patients. When theinner barrel 404 is placed within the syringe barrel 106 as shown inFIGS. 6A-6B and 7, the dosage marks on the inner barrel 404 arepositioned at one end of the major axis 422. This places the dosagemarks that are placed on the outer surface of the inner barrel 404 toproject against a narrow end 424 (FIG. 7) of the syringe barrel 106,which causes magnification of the dosage marks such that a patient canread the dosage marks easier and more readily to determine the volume ofmedicament remaining in the inner barrel 404.

In addition to improved handle and plunger features discussed above,improved syringe cap removal systems are also disclosed herein. Anillustrative embodiment of a needle tip cap is shown in FIG. 8, whichdepicts a cross sectional view of the syringe system 100 as depicted inFIG. 1A. As shown, the syringe system 100 has a needle tip cap 112 witha proximal end engaged to the distal end of the handle assembly 107. Thecomponents that form the needle tip cap 112 are next described withreference to FIGS. 9-13F. The interfitting relationship between theneedle tip cap 112 and the handle assembly 107 will be described withreference to FIG. 16A-16B.

As shown in FIG. 9, needle tip cap 112 includes an inner cap 602 thatgrips the needle assembly 101, a connector 604, and an outer cap 606.The connector 604 receives the inner cap 602 and the outer cap 606receives the connector 604 having the inner cap 602 enclosed within. Inuse, the RA patient can easily remove the needle tip cap 112 and exposethe needle by simply pulling the outer cap 606 distally from the handleassembly 107.

FIG. 10A depicts a perspective view of an exemplary embodiment of theinner cap 602. As shown, the inner cap 602 is cylindrical in shape andincludes a shoulder 902 in the proximal end. The inner cap 602 may bemade of rubbery material that allows a portion of the connector 604 todig into the surface defined by the shoulder 902 to permanently engagethe inner cap 602 to the connector 604. FIG. 10B shows a cross sectionalview of the inner cap 602 as depicted in FIG. 10A. As depicted, theinner cap 602 includes a needle receiving portion 904 that holds the tipof the needle as shown in FIG. 8. The needle receiving portion 904 maybe made from butadiene rubber. In certain embodiments, the inner cap 602is hollow.

FIGS. 11A-C show various views of the connector 604 being inserted tothe outer cap 606. As shown, the initially flower shaped connector 604,as illustrated in FIG. 13A, is bent so as to be confined within acylindrical shaped stem 610 of the outer cap 606 (FIG. 12A). As aresult, a plurality of first legs 702 a-702 d, which were initiallydisposed at about 80 degrees with respect to the horizontal are nowabout 90 degrees with respect to the horizontal. FIG. 11B shows upperinternally facing barbs 703 protruding inwardly and distally to engagethe inner cap 602 with a connection that tightens as the outer cap 606is pulled distally. This connection prevents the inner cap 602 frombeing removed when a patient pulls on the outer cap 606 distally. FIG.11C depicts a top view of the connector 604 being inserted in the outercap 606. As shown, when the connector 604 is fitted within the outer cap606, the plurality of first legs 702 a-702 d engage the inner surface605 of the outer cap 606 and the upper internally facing barbs 703protrude inwardly and distally to engage the inner cap 602. FIG. 11Calso shows the connector 604 including a second plurality of legs 706a-706 b spaced symmetrically away from one another in the distal end ofthe connector 604. In some embodiments, the second plurality of legs 706a-706 b are initially disposed more than 90 degrees (e.g., about 91degrees to about 120 degrees) with respect to the horizontal. When theconnector 604 is fitted within the outer cap 606, the second pluralityof legs 706 a-706 b make contact with the inner surface 605 of the outercap 606. In some embodiments, the second plurality of legs 706 a-706 bdig into the inner surface 605 of the outer cap 606 and remain fixed inplace during use.

The various components of the needle tip cap 112 are more particularlydescribed with reference to FIG. 12A-13F. As shown in FIG. 12A, theouter cap 606 includes a shoulder 608 and a stem 610 having a hollowinner space shaped to receive the connector 604, and a grip ring 612shaped to receive a patient's finger. The shoulder 608 includes an innersurface 622 and an outer surface 624 and flares outwardly and away fromthe stem 610, forming an orifice 618 (e.g., wider than the stem 610)into which the patient can re-insert the needle after injection. Asshown, the orifice 618 is wider than the distal end of the syringebarrel 106. In some embodiments, the orifice 618 envelopes the distalend of the syringe barrel 106 and the needle assembly 101 (FIG. 5A). Theinterfitting relationship between the outer cap 606 and the syringebarrel 106 is described with reference to FIGS. 16A-16B. The widerorifice helps reduce the likelihood that a patient will inadvertentlystab his or her self when attempting to replace the needle cap afterinjection. The stem portion 610 extends distally from the shoulder 608,which may have a cylindrical shape. FIG. 12B shows a cross sectionalside view of the outer cap 606. As depicted, the orifice 618 flaresoutwardly from the stem 610 to a proximal end 620 of the outer cap 606.FIG. 12C shows a top view of the outer cap 606. As shown, the outer cap606 is symmetrical about its center axis.

The grip ring 612 also has a finger aperture 614 to receive a patient'sthumb or other preferred finger for pulling the needle tip cap 112distally to expose the needle. In certain embodiments, the fingeraperture 614 is adapted to receive a hook that some patients use to pullthe needle tip cap 112. The outer cap 606, compared to a conventionalneedle covering cap, makes it easier for patients to engage anddisengage the needle tip cover 112 from the syringe barrel 106 as itdoes not require the patient to contort their fingers by pressing on thesides of a narrow needle cap. As noted before, many patients have goodand bad days and on bad days, some patients may experience difficultypulling the needle cover off the syringe before self-injection. The gripring 612 addresses this issue by allowing the patient to simply put thethumb or other preferred finger through the finger aperture 614 and pullthe needle tip cap 112.

FIGS. 13A-13F show various views of the connector 604. As shown in FIG.13A, the connector 604 includes the first plurality of legs 702 a-702 dspaced symmetrically away from one another. The connector 604 is made,in certain embodiments, from a thin sheet of stainless steel, formed bya tool that bends the first legs into angles with respect to thehorizontal. Such configuration and the elastic nature of these legs aidin securing the inner cap 602 to the outer cap 606.

The inner cap 602 and the outer cap 606 are also secured togetherthrough upper, internally facing barbs 703 a-703 h protruding from thefirst legs 702 a-702 d. The upper, internally facing barbs 703 a-703 hinclude tips 704 a-704 p that point toward the distal end of theconnector 604 (i.e., the needle end). As illustrated in FIGS. 13C and13D, these barbs are spaced about the perimeter of the connector 604near its proximal end, with each of the first legs (e.g., 702 a) havingtwo internally facing barbs (e.g., 703 a-703 b), and each barbcontaining a pair of barb tips (e.g., 704 a-704 b). In some embodiments,the upper, internally facing barbs 703 a-703 h are concaved as shown inFIG. 13A-13D. These barbs are shaped to engage the inner cap 602 whenthe inner cap 602 is fitted within the connector 604. More specifically,the barb tips (e.g., 704 a and 704 b) apply opposing force with respectto one another when they engage the inner cap 602 as the barb tips aredisposed at two ends of a concaved surface (e.g., upper, internallyfacing barbs 703). In some embodiments, the upper, internally facingbarbs 703 a-703 h are disposed at an angle with respect to the body ofthe first legs 702 a-702 d. This is more particularly shown in FIG. 13D.Such configuration may enhance the engagement between the inner cap 602and the connector 604 as added protrusion (i.e., angled disposition ofthe barbs 703 with respect to the first legs 702) allows the barb tips704 a-704 p to more securely dig into the inner cap 602 when a userpulls the needle tip cap 112 distally. As depicted in FIG. 13D, thelongitudinal axis 710 of the upper portion 711 of the first legs 702 bis disposed at angle α with respect to the center axis 712 of the upper,internally facing barb 703 c. The center axis 712 may be disposedbetween about 3 degrees to about 30 degrees with respect to thelongitudinal axis 710 of the first legs 702 b.

As noted above, the connector 604 contains a second plurality of legs706 a-706 b spaced symmetrically away from one another in the distal endof the connector 604. As shown in FIG. 13E, each of the second pluralityof legs contains lower, externally facing barb tips 707 a-707 d thatpoint toward the proximal end of the connector 604. These barbs engage alower, interior portion of the outer cap 606, thereby barbing theconnector 604 to the outer cap 606 in a manner similar to theconnections between the upper, internally facing barb tips 704 a-704 pand the inner cap 602 as described above. As the lower barbs 707 extendproximally into the outer cap 606, these barbs 707 prevent, incombination with the upper, internally facing barb tips 704 a-704 p, theouter cap 606 from disengaging from the connector 604.

FIGS. 14 and 15A-15B depict an exemplary mating relationship betweenvarious components of the needle tip cap 112. More specifically, thesefigures show the inner cap 602 being mated to the connector 604 and theconnector 604 being mated to the outer cap 606. As shown, the connector604 fits within the outer cap 606 and engages the inner cap 602,connecting substantially permanently to the inner cap 602, such thatafter engaged, if the outer cap 606 is pulled distally by the patient,the entire outer cap 606 and the inner cap 602 covering the needle areremoved as a unit, exposing the needle. In some embodiments the innercap 602 is asymmetrical in shape, at least one pair of legs (e.g., 702 aand 702 c) makes contact with the inner cap 602 such that when the outercap 606 is pulled, the entire outer cap 606 and the inner cap 602 wouldbe removed as a unit. In some embodiments, only one but not both pairsof legs connect with the inner cap 602.

FIG. 14 depicts a top view of the needle tip cap 112 having the innercap 602 interfitted within the connector 604 and the assembly beingfitted within the outer cap 606. As shown, only the outermost portionsof the first plurality of legs 702 a-702 d are visible in the top viewas the upper, internally facing barbs 703 have engaged the outer surfaceof the inner cap 602 and cannot be seen in the top view.

FIG. 15A depicts a perspective view of the needle tip cap 112 asdepicted in FIG. 14 with the outer cap 606 removed for viewing clarity.The upper, internally facing barbs 703 are adapted to receive the innercap 602 when the inner cap 602 is being inserted onto the connector 604in the direction indicated by the arrow (FIG. 15A), but the upper,internally facing barb tips 704 are shaped to engage the inner cap 602and prohibit backsliding of the inner cap 602 or removal of theconnector 604 from the inner cap 602 once engaged. As shown, onceengaged, the upper barbs 703 a-703 h dig into the outer surface of theinner cap 602.

FIG. 15B shows the externally facing barb tips 706 a-706 b engaging thedistal region of the outer cap 606 in a manner similar to the connectionbetween the upper, internally facing barb tips 704 a-704 p and the innercap 602. In some embodiments, the lower, externally facing barb tips 707a-707 d dig into the inner surface of the outer cap 606.

As explained above, the needle tip cap 112 is designed to enclose theneedle of the syringe system 100 and fittingly engage with the handleassembly 107. This engagement is shown in FIG. 16A, where the orifice618 (shown in FIG. 12A) of the needle tip cap 112 overlaps the needleassembly 404 that protrudes from the syringe barrel 106 and encloses thedistal end of the handle assembly 107. More particularly, the tip cap112 includes a plurality of mating protrusions 504 a-504 b formed on theinner surface 622 of the shoulder 608 (FIG. 12A). The mating protrusion504 a and 504 b engage with a pair of recesses 506 a-506 b positioned onthe syringe barrel 106. As explained above, the syringe barrel 106includes a major diameter and a minor diameter. In certain embodiments,the recess 506 a is formed at one end of the major diameter and therecess 506 b is formed at the opposite end of the major diameter. Theprotrusions 504 a and 504 b and the recesses 506 a and 506 b are shapedto allow a patient to engage and disengage the needle tip cap 112 with aminimal yet sufficient resistance to shield the needle. As shown, eachof the mating protrusions 504 a-504 b includes a top surface 510 and aside surface 512. As depicted in FIG. 12A, the mating protrusions 504a-504 b protrude from the inner surface 622 at approximately 90 degreesso that the side surface 512 is positioned perpendicular to thelongitudinal axis of the handle. The side portion 512 portion is alsodisposed perpendicularly to the top surface 510. In some embodiments,the mating protrusions 504 a-504 b have triangular cross-sectional areawith sharp edges, which allows the mating protrusions to engage therecesses 506 a-506 b. In certain embodiments, the mating protrusionshave rounded edges.

As depicted in FIG. 16B, the recesses 506 a-506 b include a proximalportion 514, a distal portion 516, and an inner mating surface 518shaped to receive the side surfaces 512 of the mating protrusions 504a-504 b. As shown, the distal portion 516 flares outwardly to guide themating protrusions 504 a-504 b and enable smoother engagement betweenthe two components. As depicted, the proximal portion 514 forms ahalf-circle 520 shape that allows the edges of the top surface 510 toengage along the curved inner mating surface 518 of the proximal portion514. In some embodiments, the recesses 506 a-506 b are tapered from theproximal portion 514 to the distal portion 516.

Aligning and mating the protrusions 504 a-504 b and the recesses 506a-506 b also orients the needle tip cap 112 and the body of the syringein the same plane, which aids in fitting the syringe system incommercial packaging, such as may be used in the sale of the biologic orother medicament.

FIG. 17A depicts an alternative embodiment of the inner cap 1300 havinga groove 1304 positioned near the proximal region of the inner cap 1300.As depicted, the groove 1304 runs along the circumference of the innercap 1300 and is adapted to receive fittings 1306 a-1306 b located on theouter cap 1302 as shown in FIG. 17B. When assembled, the distal end ofthe inner cap 1300 is inserted into the stem region 1306 of the outercap 1302 and the fittings 1306 a-1306 b fit within the groove 1304 tosecure the inner cap 1300 to the outer cap 1302.

FIGS. 18A-18D depict alternative embodiments of the needle tip cap. Asillustrated, the needle tip cap may be without a thumb ring that allowsthe patient's finger to engage the needle cap. A needle tip cap 1400 asshown in FIG. 18A includes a proximal shoulder 1402 that flaresoutwardly to receive a needle, a holding surface 1404 for allowing thepatient to hold and manipulate the needle tip cap 1400, and a distalshoulder 1406 that provides an anchoring place for patients to grab theneedle tip cap 1400. The shape of the proximal shoulder 1402 aids inpreventing accidental needle stabs. As depicted, the distal shoulder1404 includes a flat bottom surface that allows the needle tip cap 1400to stand vertically on a flat surface, which may be helpful if thepatient has difficulty grabbing small items laying horizontally flat ona surface. FIGS. 18B-18D depict alternative shapes for the thumbaperture for a needle tip cap.

To use the syringe for injection, the patient pulls on the thumbaperture 614 (FIG. 12A), thereby removing outer cap 606, the connector604, and the inner cap 602 surrounding the needle to expose the entireneedle for use. The patient is directed to hold the syringe in a waythat is comfortable for the patient and insert the needle into theinjection site at about 45 degrees to the skin. The patient then pushesthe plunger 110 until all the medicine is injected or other amountdirected and pulls the needle out. When the needle is pulled out, thepatient may re-apply the needle tip cap 112 to the needle to protectagainst subsequent inadvertent injection, and discard.

In certain implementations, the syringe system 100 is provided to thepatient in a kit including a syringe, alcohol swab, and medication. Incertain embodiments syringe system 100 is pre-filled with medication.Particular examples include viscous medications containing proteins orpeptides especially antibodies or fragments thereof, including pegylatedantibody fragments. The systems and methods may in particular be used toadminister the pegylated antibody fragment known as certolizumab pegol.The medication may be for treatment of any disease or disorder,including for the treatment of rheumatoid arthritis. In certainembodiments, the viscosity of the liquid medication is less than about120 mPa·s (120 centipoise), preferably less than 100 mPa·s (100centipoise) at a delivery temperature of 20° C. In certain embodiments,the viscosity of the liquid medication is between about 65 centipoiseand about 120 centipoise. In certain embodiments, the viscosity of theliquid medication is between about 75 centipoise and about 100centipoise. In certain embodiments, the viscosity of the liquidmedication is higher than about 65 mPa·s, preferably higher than 85mPa·s. In certain embodiments the viscosity of the liquid medication isabout 80 centipoise. In certain embodiments, the liquid medication isdesigned for refrigerated rest (e.g. at from 2-8° C.) and for injecteddelivery at room temperature (e.g. at or about 18-30° C.). It is to beunderstood that while the invention has been described in conjunctionwith the various illustrative embodiments, the forgoing description isintended to illustrate and not limit the scope of the invention. Forexample, a variety of systems and/or methods may be implemented based onthe disclosure and still fall within the scope of the invention. Otheraspects, advantages, and modifications are within the scope of thefollowing claims. All references cited herein are incorporated byreference in their entirety and made part of this application.

We claim:
 1. A syringe comprising: a handle having a first flange and asecond flange forming a handgrip; a first arc forming a bottom surfaceof the first flange contoured to correspond to a radius of an arc formedby a user's fingers; a second arc forming a bottom surface of the secondflange contoured to correspond to a radius of an arc formed by theuser's fingers and shaped flatter than the first arc; a syringe barrelhaving an outer barrel and an inner barrel, the inner barrel having aneedle mounted at a distal end of the inner barrel, the outer barrelbeing shaped to receive the inner barrel; and a tip cap releasablyengageable with a distal end of the syringe barrel for shielding theneedle comprising: an outer cap; an inner cap; and a connector shaped tofit within and engage the outer cap and engage the inner cap and havinga plurality of first legs spaced symmetrically away from one another,each first leg having a plurality of internally facing barbs pointingtoward a distal region of the connector and adapted to engage a proximalregion of the inner cap, wherein each of the plurality of internallyfacing barbs is disposed at an angle with respect to the plurality offirst legs, the connector having a plurality of second legs spacedsymmetrically away from one another, each second leg having a pluralityof externally facing barb tips located at an end of a respective secondleg and adapted to engage a distal region of the outer cap, wherein theouter barrel includes a first recess and a second recess shaped toreceive the tip cap.
 2. A syringe system comprising: a handle having afirst flange and a second flange forming a handgrip arranged for asingle-handed operation; a first open arc forming a bottom surface ofthe first flange contoured to correspond to a radius of an arc formed bya user's fingers; a second open arc forming a bottom surface of thesecond flange contoured to correspond to a radius of an arc formed bythe user's fingers and shaped flatter than the first open arc; and asyringe barrel having an outer barrel and an inner barrel and extendingdistally from the handgrip, the inner barrel having dosage marks and aneedle mounted at a distal end, the outer barrel shaped to receive theinner barrel and having an elliptical cross section to magnify thedosage marks located on the inner barrel, wherein the outer barrelincludes a first recess and a second recess shaped to receive a tip cap.3. The syringe of claim 2, wherein the handle includes a top cover and ahandle body, the top cover having a plurality of pegs adapted to matewith a set of corresponding depressions formed on the handle body. 4.The syringe of claim 3, wherein the top cover includes an aperture forreceiving a syringe plunger.
 5. The syringe of claim 3, wherein thehandle body includes an aperture for receiving a syringe plunger.
 6. Thesyringe of claim 3, wherein the handle body includes a syringepositioning pocket having a flat side.
 7. The syringe of claim 6,wherein the inner barrel includes a flange having a flat side adapted toalign with the corresponding flat side formed on the handle body.
 8. Thesyringe of claim 7, wherein aligning the flange within the syringepositioning pocket orients the dosage marks at one end of a major axisof the syringe barrel.
 9. The syringe of claim 8, wherein the major axisof the syringe barrel is longer than a minor axis of the syringe barrel.10. A syringe comprising: a syringe barrel having an outer barrel and aninner barrel, the inner barrel having dosage marks and a needle mountedat a distal end, the outer barrel shaped to receive the inner barrel andhaving an elliptical cross section to magnify the dosage marks locatedon the inner barrel; and a tip cap slidably engageable with a distal endof the syringe barrel for shielding the needle comprising: an outer cap;an inner cap; and a connector shaped to fit within and engage the outercap and engage the inner cap and having a plurality of first legs spacedsymmetrically away from one another, each first leg having a pluralityof internally facing barbs pointing toward a distal region of theconnector and adapted to engage a proximal region of the inner cap,wherein each of the plurality of internally facing barbs is disposed atan angle with respect to the plurality of first legs, the connectorhaving a plurality of second legs spaced symmetrically away from oneanother, each second leg having a plurality of externally facing barbtips located at an end of a respective second leg and adapted to engagea distal region of the outer cap, wherein the outer barrel includes afirst recess and a second recess shaped to receive the tip cap.
 11. Adrug delivery system comprising: a syringe barrel having an outer barreland an inner barrel, the inner barrel having dosage marks and a needlemounted at a distal end, the outer barrel shaped to receive the innerbarrel and having an elliptical cross section to magnify the dosagemarks located on the inner barrel; wherein the inner barrel is adaptedto receive a drug having a viscosity more than about 65 centipoise; anda tip cap slidably engageable with a distal end of the syringe barrelfor shielding the needle comprising: an outer cap; an inner cap; and aconnector shaped to fit within and engage the outer cap and engage theinner cap and having a plurality of first legs spaced symmetrically awayfrom one another, each first leg having a plurality of internally facingbarbs pointing toward a distal region of the connector and adapted toengage a proximal region of the inner cap, wherein each of the pluralityof internally facing barbs is disposed at an angle with respect to theplurality of first legs, the connector having a plurality of second legsspaced symmetrically away from one another, each second leg having aplurality of externally facing barb tips located at an end of arespective second leg and adapted to engage a distal region of the outercap, wherein the outer barrel includes a first recess and a secondrecess shaped to receive the tip cap.
 12. The drug delivery system ofclaim 11, wherein the viscosity of drug is between about 65 centipoiseto about 120 centipoise.
 13. The drug delivery system of claim 11,wherein the viscosity of drug is between about 75 centipoise to about100 centipoise.